Electric switch.



- PATENTED FEB. 28, 1905. W. H. POWELL.

ELECTRIC SWITCH.

APPLICATION FILED NOV. 25,1903.

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T Li H r f T Wu I No. 783,977. PATENTED FEB. 28, 1905.

' W. H. POWELL.

ELECTRIC SWITCH.

APPLICATION FILED NOV.28, 1903.

5 SHEETS-SHEET 2.

No. 783,977 I PATENTED FEB 28, 1905. W. H. POWELL.

ELECTRIC SWITCH.

APPLIOATIGN FILED NOV.28,1903.

5 SHEETS-SHEET 3.

in/6836s: q ilzlgiu ear: W y jfowglgv 'M m ma 9L No. 788,977. PATENTED FEB. 28, 1905. W. H. POWELL.

ELECTRIC SWITCH.

APPLIGATION FILED NOV.28,1903.

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2; 2* Off 1f Ffiwsas: Imam" WMMZLWdDL @W 27% y dw mgfi No. 783,977. PATENTED FEB. 28. 1905. W. H. POWELL.

ELECTRIC SWITCH.

APPLIOATION FILED NOV.28,1903.

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Witnesses: 7 T Q r 6M4 W POI 76a WM by g w UNITED STATES Patented February 28, 1905.

PATENT OFFIc WVILLIAM H. POWVELL, OF EAST ORANGE, NEV JERSEY, ASSIGNOR TO CROCKERJVHEELER COMPANY, OF AHPERE, NEW JERSEY, A GOR- PORATION OF NEV JERSEY.

ELECTRIC SWITCH.

SPECIFICATION forming part of Letters Patent No. 783,977, dated February 28, 1905.

Application filed November 28, 1903. Serial No. 183,048.

To aZZ- whom it may concern/.-

Be it known that 1, WILLIAM H. POWELL, a citizen of the United States of America, and a resident of East Orange,county of' Essex, State of New Jersey, have invented certain new and useful Improvements in Electric Switches, of which the following is a specification.

This invention relates to electric switches wherein a number of terminals are connected in various ways at different positions of the switch.

With this invention the connections are offected by a plurality of' sets'of switch-arms projecting from a rotatable member and contacting when the rotatable member is rotated to different positions in various ways with fixed switch-contacts which are suitably placed around the rotatable member. Eachof' the sets of switch-arms is preferably in the form of a disk or ring the periphery of which is provided with suitably positioned switcharms all lying in the same plane, which are brought into contact with the fixed contacts, so as to effect the required connections at the successive positions of the rotatable member. The switch is so designed that the switch-arms and the fixed contacts may be'stamped from sheet metal and put together with a minimum expense for labor and a switch produced of exceptionally compact design in view of the number and variety of connections to'be effected. This switch has been made with especial reference to the electrical connections required in the regulation of electric motors on a multiple-voltage system such as set forth in United States Letters Patent, N 0. 735,352 granted August A. 1903, on an application by (irano S. Dunn; but many of the features herein set forth are applicable in the control and switching of electric current for other purposes.

Referring to the accompanying five sheets of drawings, which form a part of' this application, Figure 1 is a longitudinal section through a switch embodying my invention. Fig. 2 is a section on the line 11 H of Fig. 1, showing the mechanism for latching the switch in the successive positions. Fig. 3 is a secnections are effected by the switch.

tion on the line III 111 of Fig. 1, showing a plan view of the sets of switch-arms and fixed contacts. Figs. A to 11 are elevations of the eight terminals with the fixed contacts attached thereto, between which electrical con- Fig. 12 is a plan of the switch with a diagram of the connections to an electric-motor armature and field and to the conductors of a multiple-voltage system. Fig. 13 shows four diagrams forming an analysis of ring 1 of the switch and the fixed contacts cooperating therewith. Fig. let shows these diagrams combined to illustrate the method of designing ring 1 of the switch. Fig. 15 shows three diagrams forming a similar analysis of ring 2 of the switch. Fig. 16 shows these diagrams combined to illustrate the method of designing ring 2. of the switch. Fig. 17 shows three diagrams forming a similar analysis of ring 3 of the switch. Fig. 18 shows these diagrams combined to illustrate the method of designing ring 3 of the switch. Fig. 19 shows three diagrams forming a similar analysis of ring A of the switch. Fig. 20 shows these diagrams combined to illustrate the method of designing ring A of the switch. Fig. 21 shows each of the four rings in its relation to the fixed contacts cooperating therewith and indicates the electrical connections which are made in each of the eight positions of the switch. Figs. 22 to 25 show the four rings of the switch with their switch-arms and the fixed contacts cooperating therewith in their relation at the off position of' the switch and on the same scale as Figs. 1, 2, and 3.

The rotatable member of the switch comprises four rings or fiat disks 1 2 3 4, each provided with radial switch-arms. The rings are insulated from each other by interposed disks of insulation 1. Some of the disks of insulation are of sufficient diameter to form partitions between the switch-arms projecting from different rings. It is desirable that each ring should be used to effect connections with only one of the conductors of the multiple-voltage system, so that only one potential will be required in the compartment with any one ring.

In the specific application of the switch which is illustrated there are four conductors, between which differences of potential are maintained, and it has been found practicable to effect all the connections to any one conductor with switcharms on one ring, and the switch therefore has as many rings or sets of switch-arms as there are conductors. The switch is designed to connect in its different positions the two armature-terminals to the different pairs of the four conductors in all the combinations for different voltages in one direction, there being six in number, and in addition the switch has an off position and one reverse position with the armature-terminals connected to the terminals of the conductors, between which the lowest potential difference is maintained. The switch therefore has eight positions, and for the sake of compactness and symmetry of structure these positions are at one-eighth divisions of the circle. Besides effecting the motorarmature connections to the conductors the switch is constructed so as to connect the motor-field terminals to two of the conductors in all positions of the switch except the off position and to break these connections to both terminals of the field in the off position. These field positions may be omitted if it is not desired to open the field in the off position of the switch every time that the switch is operated to stop the motor.

Eight terminals are provided on the switch, two terminals, A and AA, for the motor-armature, two terminals, f and f, for the motor-field, and four terminals, (4 7) a (Z, for the four conductors of the multiple-voltage system. The first or lowest potential difference is maintained between the terminals (L and I), the second between terminals 0 and (Z, the third between terminals band 0, the fourth between terminals (0 and c, the fifth between terminals 0 and (Z, and the sixth and highest potential difference is maintained between terminals a and (Z by reason of the connection of these terminals to the conductors of a multiple-voltage system such as is set forth in the patent above referred to. The switch is designed to connect the armature-terminals to the conductors at successive positions in the above-emnnerated order.

The terminals to be connected by the switch at the several positions will therefore be as follows:

. l Rim;- 1. v Ringfl. l Ring l.

AA (4f A of Second forward, f Third forward. 3) i Fourth forward, l- 4).. A of Fifth forward, a Sixth forward. 1- 0 The positions for the switch-arms and the fixed contacts for each ring are determined by the sequence of the contacts as given in the table; but as the contact-arn'is of each ring are all in the same plane an arrangement of arms and contacts which will give the required connections at the proper positions will be liable to make harmful connections at other positions unless certain rules of design are observed. There are two rules by the observance of one or both of which such harmful connections may be avoided if too many connections with one ring are not undertaken. These are, first, to make the lengths of the contact-arms and the distance of the fixed contacts from the axis of the switch unequal, and, second, to so dispose the switch-arms and fixed contacts around the circle that they will have different angular spacings. In observing the first condition and making the fixed contacts of unequal length the fixed contact at the greatest distance from the axis will only contact with the longest switch-arm and will be beyond the paths of the other switch-arm, the next nearer fixed contact or contacts will contact with both the longest and next to the longest switch-arm, and the fixed contacts nearest to the axis will contact with all the switch-arms. In determining which fixed contacts to place nearest and which farthest from the axis a solution of the problem is most likely to be found if the contact which is required in the fewest number of positions is placed farthest from the axis, and the contact which is next in frequency is the next nearer contact to the axis, and the contact which is required in the greatest number of positions is the nearest to the axis. The positioning of switch-arms and fixed contacts with respect to ring 1, since this makes the greatest number of contacts and is the most complicated, should be determined first. There are four fixed cont-acts around this ring, and inspection of the table shows that contact is to be made with fixed contact AA in one position, with contact A in three positions, and with contacts (L and fin seven positions. Consequently contact AA should be farthest from the axis, contact A should be next nearer, and contacts a or f should be nearest to the axis. It is immaterial which of these two latter contacts is nearest, since they are made at the same positions, and in any switch arrangement the switch would operate the same if the conductors connected to them should be exchanged. ith respect to the three fixed contacts (1/, AA, and A, it will be seen that the general statement may be made that connections are to be effected by the switch-arms at a plurality of positions of the ring between the contact (0 and one or the other of the two other fixed contacts AA and A. It will also be seen that at no position of the ring are the second two fixed contacts to be connected to each other. This statement is also true if fixed contact f be read in lieu of fixed contact a. A proper disposition of the switch-arms around the ring can be determined by assuming and drawing a separate ring with suitably-positioned switch-arms for each fixed contact and then superimposing the figures in such a manner that the fixed contacts will occupy different positions around the circle, and the open positions in the diagrams of the shorter switch-arms will not be covered by any of the switcharms of the diagrams with longer switch-arms, so far as this can be done.

The four diagrams of Fig. 13 show such an analysis of ring 1, and Fig. 14 shows these four diagrams superimposed in accordance with the conditions above laid down. In these diagrams the switch-arms or part of each switch-arm which contacts with any fixed contact in the reverse position is marked 1, and the switch-arms which contact with the fixed contacts in the six forward positions of the switch are marked with the numerals l 1, 2, &c., to 6. 1n laying out the diagrams which are to compose the ring the points of the forward positions are numbered consecutively around the ring in counter-clockwise direction, and the switch-arms are provided at the required angular positions, so that retation of the rings in a clockwise direction will bring the positions opposite the fixed contacts in the same order, and the switch-arms will contact with the fixed contacts at the required positions of the switch. The positions at which switch-arms are omitted will be termed the open positions. As the field connection is the same in each of the operative positions of the switch and as the rupture of this connection is attended with a consider able spark, it is desirable that it should only be broken in passing to the off position. Hence instead of providing contact places at the ends of the independent switch-arms the contact places are on the periphery of the ring, which is notched at the off position only. Proceeding in the above-described manner results in the four diagrams of Fig. 13, each of which is drawn to show the required relation in the off position of the switch between the switcharms and the fixed contact for which the switch-arms are provided. If these diagrams are redrawn on separate transparent sheets and superimposed, it is a simple matter to so place them on each other that the fixed contacts will lie at different positions around the ring and, subject to this condition, also so position the diagrams that the switch-arms of the diiferent diagrams will in large measure also be superimposed and as much as possible avoid covering any of the open positions of the diagrams with the shorter switch-arms and lesser number of open positions by the switch arms of the diagrams with longer switch-arms-i'or example, in the diagram for A by the switch-arm or diagram for AA. The open position in the diagram for f should not be covered by either of the switch-arms ol:' the diagrams for A or AA, and the open position in the diagram tor a should not be covered by the contact positions or switcharms of either of the other three diagrams. In this particular case in endeavor-ing to apply the above rules it is not found possible to avoid covering the open position in the diagram tor (1. Since the diagram for a and for f must be so shifted that the fixed contacts a and 7 will occupy different positions around the circle and, when this is done, since there is but one open position in each ring and this is opposite the fixed contact, the open position of the smaller ring will necessarily be covered by some parts of the periphery of the larger ring. N o harm, however, results from the covering of a single open position, since this may result only in a single contacting of the ring with some fixed contact when no connection is required, and no current will flow by reason of open positions being opposite all of the other fixed contacts. There are a number of ways in which the diagrams here shown may be combined so as to satisfy the conditions above laid down to an equal degree, and several, at least, which have been tested by me result in a ring which is suitable for an operative switch, and Fig. 1% is one of several solutions of the problem. That it will give the required connections and no false connections is proved by drawing the ring in the successive positions to which it is brought by the operation of the switch, and this is done in the first column of Fig. 21. An inspection of the figures in this column shows that the required connections are made and no others. Dotted lines connect the fixed contacts between which there is a flow of current. In the oil position, in which no connections are required, the fixed contact a happens to be in contact with the ring; but as no other fixed contact touches the ring no objectionable electrical connection is effected.

in each of rings 2, 3, and 4 the conditions as to connections to be effected and connections to be avoided, a general statement may be made similar to that above made respecting ring 1 by substituting in respect to ring 2 fixed contact for contact (I, of ring 1, in respect to ring 3 by substituting fixed contact 0 for contact a, and in respect to ring at by substituting either fixed contact (Z orf for contact (b.

Each of the other rings is constructed by first separately drawing the switch-arms for each contact in the same manner as for ring 1; but in superimposing the diagrams it is necessary not only that the different fixed contacts around each ring should occupy different angular positions around the circle, but that they should occupy positions not taken by other fixed contacts for the rings previ ously designed. it is also desirablercspecting the fixed contacts, as in the case with the contacts A and the contacts A A, which conwill be required for the terminal of each conductor which is brought to the switch. In working out the problem for the switch which is illustrated this is essential, since there are only eight positions and eight different conductors are brought to the switch. Rings constructed in accordance with the directions above given are shown in Fig. 16, Fig. 18, and Fig. 20. These were drawn in all the switch positions in the manner indicated above in columns two, three, and four of Fig. 21. On inspecting these figures it was found that in the case of ring 3 one of the group of three switch-arms in consecutive positions, which wai made shorter than the other two in Fig. 18, could be lengthened to the same length without introducing any harmful connection, such harmful connection being avoided by reason of the unequal spacing of the four switch-arms, and this ring is therefore simplified, as shown in Fig. 21 and Fig. 24:, by providing it with switch-arms of only two different lengths.

In the foregoing discussion the endeavor has been to lay down general rules for the design of switches to effect prescribed connections at various assigned positions of the switch with as few parts as possible. Conditions arise in electrical work where a variety of connections are required to be made as, for example. in efiecting resistance combinations, in which there will be a larger number of positions than is the case with the specific example above discussed, where it is immaterial whether the connections are made or not. In such a case in drawing the separate ring diagrams, in addition to showing where switch-arms are required and where switcharms must be omitted, the remaining positions will be indicated as being positions where it is immaterial whether the switcharms are present or not. The diagram with the least number of open positions should be the smallest and the diagram with the least number of required positions should be the largest.

The base of the rotatable member of the switch is a plate g, which carries a bolt it. The bolt in each of the positions of the switch engages a hole in a ring Zr, which is attached to the base of the switch. The switch is operated from a handle L, which is attached to a hollow spindle M, that passes through a sleeve s in the rotatable member of the switch. A coil-spring N is contained in the hollow spindle. The ends of the spring are turned outwardly and pass through a slot in the side of the spindle and engage the sides of a slot in the sleeve of the rotatable member. Each of the slots has a width equal to one-eighth of the circle plus the diameter of the spring-wire, so as to permit the spindle to be rotated onceighth of a revolution independently of the rotatable member. The slots are of equal width from end to end and of suflicient length to engage both ends of the spring. Rotation of the spindle effects the withdrawal of the bolt by reason of the engagement of corners a on the lower end of the spindle with the bolt. As soon as the bolt is withdrawn the coil-spring snaps the rotatable member to the next position.

What I claim as new, and desire to secure by Letters Patent of the United States, is-

1. In an electric switch, the combination of a rotatable member, a set of switch-arms carried by the rotatable member, the switch-arms being interconnected and radially disposed in the same plane around the axis of the rotatable member, and a plurality of fixed contacts in the paths of the switch-arms, the fixed contacts and switch-arms being so positioned that connections will be effected by the switcharms at a plurality of positions of the rotatable member between one of the fixed contacts and one or the other of two other fixed contacts without connecting the second two fixed contacts to each other, substantially as described.

2. In an electric switch, the combination of a rotatable member, a set of switch-arms carried by the rotatable member, the switch-arms being interconnected and radially disposed in the same plane around the axis of the rotatable member and projecting to unequal dis tances from said axis, and a plurality of fixed contacts at unequal distances from the axis, the fixed contact farthest from the axis being in the path of the longest switch-arm and beyond the path of the shortest switch-arm, and the fixed contact nearest to the axis being in the paths of all the switch-arms, the fixed contacts and switch-arms being so positioned that connections will be effected by the switch-arms at a plurality of positions of the rotatable member between one of the fixed contacts and one or the other of two other fixed contacts, substantially as described.

3. In an electric switch, the combination of a rotatable member, a set of switch-arms carried by the rotatable member, the switch-arms being interconnected and radially disposed in the same plane around the axis of the rotatable member and projecting to unequal distances from said axis, and a plurality of lixed contacts at unequal distances from the axis, the fixed contact farthest from the axis being in the path of the longest switch-arm and beyond the path of the shortest switch-arm, and the fixed contact nearest to the axis being in the paths of all the switch-arms, the fixed con tacts and switch-arms being so positioned that connections will be effected by the switch-arms at a plurality of positions of the rotatable member between one of the fixed contacts and tween which different potentials are mainone or the other of two other fixed contacts Without connecting the second two fixed contacts to each other, substantially as described.

4. In a multiple-voltage switch, the combination of a rotatable member, a plurality of sets of switch-arms carried by the rotatable member, the switch-arms of each set being interconnected and radially disposed in the same plane around the axis of the rotatable memberand the sets of switch-arms being in different planes and insulated from each other, a plurality of fixed contacts between which different potentials are maintained, each of which is in the path of a different set of switcharms, and two sets of fixed contacts, the contacts of each set being interconnected and in the paths of different sets of switch-arms, substantially as described.

5. In a multiple-voltage switch, the combination of a rotatable member, a plurality of sets of switch-arms carried by the rotatable member, the switch-arms of each set being interconnected and radially disposed in the same plane around the axis of the rotatable member, and the sets of switclrarms being in different planes and insulated from each other, a plurality of fixed contacts between which different potentials are maintained, each of which is in the path of a different set of switcharms, and two sets of fixed contacts, the contacts of each set being interconnected and in the paths of different sets of switclrarms, the fixed contacts and switch-arms being so positioned that connections will be effected by the switch-arms at a plurality of positions of the rotatable member between one or the other of the two sets of fixed contacts and one of the other fixed contacts, substantially as described.

6. In a multiple-voltage switch, the combination of a rotatable member, a plurality of sets of switch'arms carried by the rotatable member, the switch-arms of each set being interconnected and radially disposed in the same plane around the axis of the rotatable member and projecting to unequal distances from said axis, and the sets of switch-arms being in difi'erent planes and insulated from each other, a plurality of fixed contacts betained, each of which is in the path of a different set of switch-arms, and two sets of fixed contacts, the contacts of each set being1nter- 1 connected and in the paths of different sets of switch-arms, the fixed contacts for each set of switch-arms being at unequal distances from the axis so that the fixed contact farthest from the axis will be in the path of the longest switch-arm and beyond the path of the shortest switch-arm, and the fixed contact nearest to the axis will be in the paths of all the switcharms, the fixed contacts and switch-arms being so positioned that a plurality of connections between the fixed contacts will be efi'ected by the sets of switch-arms at each of a plurality of positions of the rotatable member, substantially as described.

7. In a multiple-voltage switch, the combination of a rotatable member, a plurality of sets of switch-arms carried by the rotatable member, the switch-arms of each set being interconnected and radially disposed in the same plane around the axis of the rotatable member and projecting to unequal distances from said axis and the sets of switch-arms being in ditlerent planes and insulated from each other, a plurality of fixed contacts between which dill'erent potentials are maintained, each of which is in the path of a different set of switch-arms, and two sets of fixed contacts, the contacts of each set being interconnected and in the paths of different sets 01 switch-arms, the fixed contacts for each setol switch-arms being at unequal distances from the axis so that the fixed contact farthest from the axis will be in the path of the longest switch-arm and beyond the path of the shortest switch-arm and the fixed contact nearest to the axis will be in the paths of all the switcharms, the fixed contacts and switch-arms being so positioned that a plurality of connections will be effected by the sets of switcharms at each of a plurality of positions of the rotatable member between one or the other of the two sets of fixed contacts and one of the other fixed contacts without connecting the two sets of fixed contacts to each other, substantially as described.

Signed by me at East Orange, New Jersey, this 27th day of November, 1903.

\VILLIAM H. POlVELL.

Vitnesses:

SAMUEL XV. BALcir, E. R. DOUGLAS. 

